Glycine Max Merrill Cv Research Articles

Metabolism of [ring‐2,6‐14]parathion in plant cell suspension cultures of carrot (Daucus carota), purple foxglove (Digitalis purpurea), soybean, thorn apple (Datura stramonium) and wheat (Triticum aestivum)

AbstractBy means of standardized procedures, the metabolism of [ring‐2,6‐14C]‐parathion was investigated in carrot (Daucus carota L.), purple foxglove (Digitalis purpurea L.), soybean (Glycine max Merrill cv. ‚Mandarin’︁, and Glycine max Merrill cv. ‚Harosoy 63’︁ cultivated on B5 and Miller media, respectively), thorn apple (Datura stramonium L.), and wheat (Triticum aestivum L.) cell suspension cultures. In the wheat and soybean (Mandarin) cells only 2.9 and 8.9%, respectively, of the applied parthion remained unmetabolized after 48 h of incubation, while 51.2, 57.9, 60.3, and 62.4% of the unchanged parent were detected in the D. purpurea, D. Stramonium, carrot and soybean (Harosoy) cultures, respectively. In all suspensions, paraoxon and 4‐nitrophenol were found as phase I metabolites, thus demonstrating that plant tissues can catalyse oxidative desulfuration and dearylation of parathion. 4‐Nitrophenol was also glycosylated with glucose and possibly galactose. Further, as yet unidentified, metabolites indicated that bio‐transformations had also occurred at the aromatic moiety. Large amounts of non‐extractable residues were detected in the wheat suspension (38.3%), while the other cultures showed a lower incorporation of 14C into insoluble cell material (0.9‐9.4%). For a prospective ecotoxicological evaluation of the metabolic fate of pesticides and xenobiotics in plants in general, the differential metabolic capacity of plant cell cultures and plants should be taken into account.

The Maillard reaction and oxidative stress during aging of soybean seeds

The chemical reactions that may lead to the loss of seed viability were investigated both during the accelerated aging and natural aging of soybeans (Glycine max Merrill cv. Chippewa 64). Under conditions of accelerated aging (36°C and 75% RH), fluorescence of soluble proteins accumulated, which was closely correlated with the loss of seed germinability and vigor. We were able to show this correlation by using partially purified proteins for the assay. Fluorescence also increased in seeds under good storage conditions (5°C for up to 21 years), although there was a less significant correlation between seed viability and the accumulation of fluorescent products during the time of natural aging. The rise in protein fluorescence is interpreted as an increase of Maillard products. The carbonyl content of soluble proteins (a measure of the oxidative damage) did not change significantly during either accelerated aging or natural aging: however the elimination of carbonyls during germination seemed to be hindered in seeds that had poor germination. The Maillard reaction may be a consequence of the formation of reducing sugars through a gradual hydrolysis of oligosaccharides during aging. Preliminary evidence from the natural aging study showed that, when seeds were in the glassy state, the sugar hydrolysis was inhibited. These results suggest that the Maillard reaction and oxidative reaction may play an important role in seed deterioration.

The glassy state and accelerated aging of soybeans

Deteriorative changes in seeds may be expected to reflect changes in physical state as well as in chemical composition. In the present study, measurements of changes in glass transition, lipid phase transition and sugar content were made during accelerated aging of two cultivars of soybeans (Glycine max Merrill cv. Chippewa 64 and cv. Hodgson 78). The glass transition in axes, as measured by the thermally stimulated depolarization current method, showed gradual decreases in both magnitude and transition temperature during accelerated aging, and eventually, axes of seeds lost their ability to enter the glassy state. Sucrose, raffinose and stachyose contents in seed axes showed little or no change during the aging treatment. Membrane lipids in aged axes retained the liquid crystalline phase during aging. These data suggest that the changes of glass transition during accelerated aging occurred without associated changes in soluble sugar contents or changes in the liquid crystalline state of membrane lipids. The loss of the glass transition during accelerated aging could be a consequence of the annealing effect due to elevated temperature and moisture content. We propose that a loss of the glassy state during accelerated aging leads to an enhanced rate of subsequent deteriorative reactions in seeds and accelerates the loss of viability.

The Antioxidant Status of Soybean (Glycine max) Leaves Grown Under Natural CO2 Enrichment in the Field

The effects of progressively higher CO2 levels on the foliar antioxidant status were studied by growing soybean (Glycine max Merrill cv. Cresir) plants at decreasing distances from natural CO2 sources of geothermal origin in central Italy. When compared with neighbouring controls grown under normal CO2 concentration (C), soybean leaves grown at 2 × C, 7 × C and more than 20 × C showed a substantial reduction in the size of ascorbate pool and in the activity of Cu,Zn-superoxide dismutase; both the content of ascorbic acid and the activity of ascorbate peroxidase declined at 2 × C and 7 × C and recovered to the control values at 20 × C. The foliar titre of glutathione disulfide and the activities of glutathione disulfide reductase and Mn-superoxide dismutase progressively increased as CO2 concentration increased in ambient air. The results obtained suggest that the immanent risk of dioxygen toxicity associated with photosynthetic electron flow could be reduced in the presence of high CO2 levels. On the other hand, depending on both the CO2 exposure regimes and the cell compartment considered, high CO2 could promote oxidative processes which cause GSH oxidation and require an enhanced cellular ability to scavenge superoxide anion and hydrogen peroxide.

The Metabolism of 14C-adenine and 14C-isopentenyl Pyrophosphate by Soybean Explants, Flowering and Fruiting in vitro

Summary Nodal explants of soybean Glycine max Merrill cv. Impala were grown in vitro and induced to flower and set fruit on a medium containing either 14C-adenine or 14C-isopentenyl pyrophosphate in order to investigate the possibility of these substances being incorporated into cytokinins. Labelled isopentenyl pyrophosphate was incorporated into several substances, none of which had similar chromatographic properties to the authentic cytokinin standards used. Radioactive derivatives of adenine produced after 3 months were concentrated in the flowers. Examination of these radioactive adenine derivatives by HPLC revealed that incorporation was achieved into substances which had similar retention times to those of adenosine, tZ, cZ, DHZR and 2iP. Chemical treatment of some of these peaks was carried out to learn more about their nature. Proof of incorporation of adenine into cytokinins was not conclusive. The possible role of adenine in the flowering of plants is discussed.

Inhibition of cytokinin‐induced plant growth by jasmonic acid and its methyl ester

Effects of jasmonic acid, methyl jasmonate and ABA on cytokinin‐induced soybean (Glycine max Merrill cv. Kingen No. 1) callus growth and radish (Raphanus sativus L. cv. Comet) cotyledon growth were studied. Jasmonic acid and methyl jasmonate were powerful inhibitors of kinetin‐ or N‐phenyl‐N′‐(2‐chloro‐4‐pyridyl)urea‐induced soybean callus growth, the former being more effective than the latter, especially at low concentrations (0.45 to 4.5 μM). These compounds could completely eliminate kinetin‐ or N‐phenyl‐N′‐(2‐chloro‐4‐pyridyl)urea‐induced soybean callus growth at 45 μM. At low concentrations ABA had no effect but at 450 μM it completely eliminated callus growth induced by kinetin. Of the compounds tested ABA was the most powerful inhibitor of radish cotyledon growth in the presence or absence of kinetin. Jasmonic acid and methyl jasmonate were much less effective than ABA in this assay system.